In the Ten-Gen era, Yun Zhongxuan the Seventh Prince, who possesses great power and is also the Crown Prince of the Kingdom of Rei, had closed himself off emotionally due to repeated assassination attempts and betrayals. One day, Zhongxuan meets his new servant, Youli. Although he tries to take jabs at Youli, who seems a bit scatterbrained from the very first day, Zhongxuan begins to take an interest in the young man’s unyielding spirit. After Youli saves him from being poisoned, Zhongxuan opens his heart to him. “Swear to serve me until the day you die. Do you understand, Youli?” And three years later, the day when Zhongxuan will come of age, the first step toward fulfilling his dream, is just one day away. (Source: BeLTOON, translated)